When to suspect tinea; a histopathologic study of 103 cases of PAS-positive tinea

The histopathologic features of tinea vary widely and its diagnosis could be easily missed if the index of suspicion is not high. We aimed in this study to detect histopathologic features that could be a clue for diagnosis

We retrospectively reviewed 103 cases of tinea, confirmed by Periodic acid-Schiff (PAS) staining. For each case, gender, biopsy site, and pre-biopsy suspicion were recorded. The presence or absence of 17 microscopic features was noted.

Concordance between pre-biopsy and histopathologic diagnosis was noted in 57.28% of cases, suggesting that the diagnosis is often not suspected clinically. Among the histopathologic features studied, a compact stratum corneum (either uniform or forming a layer beneath a basket weave stratum corneum), parakeratosis, mild spongiosis and neutrophils in the stratum corneum and within the blood vessels were the most frequent features noted.

This study suggests histopathologic clues that should prompt the pathologist to order a PAS stain, especially when diagnosis is not suspected clinically.